Where does selenium come from?

1 Answer

Selenium (Se) is a non-metallic element that occurs naturally in the earth’s crust at concentrations of approximately one twentieth of a part per million. Se occurs in various forms, ranging from a grey metallic to a reddish glassy appearance, and is found in various rocks and minerals, coal, and oil. Canada is among the world’s largest producers of Se. The main markets for Se are electronics and photography, glass manufacturing, pigments, additives for metal processing, and agricultural/biological applications (e.g., as an additive to animal feeds and fertilizers). These, and other activities by humans, like copper refining operations and burning of coal and oil, release Se into the environment. The major natural sources are the weathering of rocks, soils, and minerals, volcanic activity, and deposition (for example, through rainfall) of Se compounds present in the atmosphere.